SYMPTOMS AND LESIONS 45 



often normal, petechiae not infrequent. Hemor- 

 rhages and destruction of epithelial cells probably 

 due to filterable virus. "Button ulcers " due to 

 B. suipestifer, possibly to other organisms. 

 Necrotic patches usually due to Bact. necro- 

 phorus. 



Lower colon and rectum. Usually normal or 

 nearly so. Sometimes congested. Infrequently 

 the lower colon shows the same change as the 

 upper colon. 



Larynx. Mucosa frequently normal. Some- 

 times congested, more often dotted with petechiae 

 caused by filterable virus. 



Trachea and bronchi. Mucosa often normal. 

 Sometimes congested. Probably due to filterable 

 virus. 



Lungs. Very often normal. Primary lesions 

 sometimes caused by filterable virus consist of 

 ecchymoses visible beneath the pleura. These ap- 

 pear most frequently on the cephalic and cardiac 

 lobes, but are not confined to these parts. 



Terminal pneumonia due to filterable virus plus 

 nonspecific secondary invaders. Often affects all 



cular coat. When sections of such an ulcer are stained with 

 aniline dyes and examined under the microscope, the submucous 

 tissue is very much thickened, infiltrated with round cells and con- 

 taining a large number of dilated blood vessels. Eesting upon 

 this thickened submucosa, is a line of very deeply stained amor- 

 phous matter, and upon this is situated the necrotic mass which 

 fails to retain the coloring matter and which is permeated by a 

 very large number of bacteria of various kinds. Frequently the 

 eggs of trichocephalus are imbedded in the slough." Moore, 

 Pathology of Infectious Diseases. 



